1970 Ford Ranger with 302 vibration after spark plug change

[5feeney]

Hello all
I am new and first post. And still have an awful lot to learn
Just bought this truck and it was running but working thru issues.
Started and drove ok but rough. PO added headers with 3” collectors that were all jammed up against trans case and they even had to cut a piece of cross member to work it in.
I started by replacing the headers with a 2.5” collector to get the clearance I need, fixed the cross member and put in new 2-1/4 inch exhaust, mufflers and back tailpipes.
I changed the spark plugs but kept the wires as they seemed in decent shape. I have now double checked all the plugs and wires and know all to correct plug. Tuned the Edelbrook carb and now she starts right up, and idling at 930. I did notice the left set screw on the carb may not appear to be working properly, all the way in our out not resulting in any change in how she runs.
But how after the plug change as soon as I put her in drive she starts vibrating hard. thought it could be a misfire and why checked all plugs and wires multiple times now. Yesterday I checked timing and adjusted the HEI distributor. She still starts right up and idles good but same hard vibration in drive.
I have not driven her like this so not to cause any damage so not sure what happens at higher speed.
It was not vibrating before I did this work. Figure I could change the spark plugs wires next but if it’s not that wondering what I need to look at next? I am a newbie and learning as I go so any advice would be appreciated. Thanks
Jim

[DuckRyder]

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